1. Field of the Invention
This invention relates to new aqueous germicidal compositions useful for reduction or prevention of environmental and contagious mastitis in dairy animals. In particular, the invention relates to aqueous compositions containing anti-microbial agents and film forming agents used to form a protective, germicidal film on the teats and the ends of the teats of dairy animals such that the animals' skin is physically protected from pathogenic organisms and extraneous material.
2. State of the Art
Various compositions are available to dairy operators for the purpose of germicidal disinfecting of the skin surfaces on the teats of dairy cows. In addition to providing a germicidal disinfectant, there are compositions available that establish a barrier film such that the disinfected teat skin is physically protected from the unhindered reintroduction of pathogens back onto the teat skin surface. Various of the film forming compositions will also form a plug of material at the opening of the mammary sphincter to provide protection from the introduction of pathogenic organisms into the mammary canal. The control of pathogenic organisms on the teat skin of dairy cows is a major goal of the dairy industry. Contact with the bovine mammary gland by a pathogenic microorganism, usually bacteria but occasionally yeast or fungi, can result in the disease of mastitis. Mastitis is a serious infection which can in severe cases, cause death to the dairy cow and even in much milder cases can result in long term damage to the cow, loss of milk production for the dairy farmer and overall an unacceptable increase in costs to the farmer.
Mastitis is indeed widely considered to be the single most costly disease in the dairy industry. Efforts to control the presence of infectious agents date back to the early 1900's but the success of these efforts was limited by the unavailability of effective germicidal agents. The incidence of mastitis has decreased over the last twenty-five years due to the realization that proper hygiene, particularly with regard to the udder and teat surfaces of the cow is very important and due to the widespread acceptance of the practice of dipping the cows teats in a germicidal agent after milking.
Modern vacuum milking machines have perhaps made teat dipping more critical. Vacuum milking causes a relaxation of the sphincter muscle at the end of the teat canal resulting in an open canal which may require several minutes to hours to contract and close. This open period proffers a direct access route, a veritable highway for microbes, leading to the mammary gland. Dipping the teat in a disinfectant immediately after milking has been shown to be an economical and effective measure in helping to reduce the incidence of mastitis infection. Many disinfectant agents have been used in teat dips, among them: iodine, chlorine, chlorine dioxide, chlorhexidine, fatty acids, anionic surfactants and quaternary ammonium compounds.
These disinfectant agents are generally useful for helping to reduce the bacterial population on the teat skin. Mastitis still persists as the significant dairy cow disease which indicates that the current products do not address all areas of concern. It is an ironic twist that some of the available teat dip agents, notably iodine and chlorine, may in fact, contribute to the mastitis problem by causing irritation of the teat skin, thus providing an opportunistic site which promotes infection. Many available teat dip formulations attempt to combat this potential for irritation by incorporating emollient agents in an effort to soothe the skin. Additionally, some of the more powerful disinfectants, chlorine for example, can be particularly noxious for the user as well. Others such as fatty acids and anionic surfactants are not broad enough in their antibacterial spectrum to provide complete protection.
Regardless of which germicidal agent is employed or how it is formulated, the ultimate objective of teat sanitation is to minimize teat contamination for as long as possible. It is on this point that conventional teat dips fail. Once germicidal activity of the teat dip ceases, there is no control of environmental pathogens which may be encountered by the teat skin and open mammary canal. Recent product developments have sought to provide better environmental pathogen protection by bringing forth new teat dips referred to as barrier dips. These products seek to provide an antimicrobial agent as well as a coating for the teat skin and a plugging of the open teat canal.
Efforts have been made to protect cows during the vulnerable post milking period by attempting to seal the teat skin and sphincter opening with a barrier type teat dip. Many approaches to preparing barrier teat dips have been tried with varying degrees of success. Barrier dips have heretofore been composed of numerous film forming agents with and without the incorporation of antimicrobials into the compositions. Teat dip compositions containing cellulosic film formers are disclosed in U.S. Pat. Nos. 4,330,531 and 4,376,787. U.S. Pat. No. 4,022,199 discloses a teat dip composition comprising solvent gum and water mixtures. Synthetic polymers are disclosed as film forming agents in U.S. Pat. No. 5,017,369. The use of latex as a film forming agent is disclosed in U.S. Pat. No. 4,113,854, and the use of fats or oils in teat dip compositions is illustrated in U.S. Pat. No. 3,222,252.
None of the present approaches has been found to be entirely satisfactory. Some film forming agents, such as cellulose form dry easily cracked coatings that could easily be breached by pathogenic organisms. In other cases the germicides, solvents, or the film forming agents or polymers themselves can be potentially irritating. Still other compositions such as oil based products can be too difficult to remove even with a detergent product and some of the polymer films can be brittle, insoluble and difficult to remove. It can be seen that there is still the need for an improved, durable, adherent, flexible but readily removable film forming barrier teat dip composition that is non-irritating to the teat skin and compatible with a number of effective germicidal agents.